JP7409011B2 - Belt conveyance device, image forming device, and belt conveyance device control method - Google Patents

Description

The present invention relates to a belt conveying device, an image forming apparatus, and a method of controlling the belt conveying device.

The image forming apparatus includes a belt conveyance device for conveying a recording medium. The belt conveyance device has a configuration in which an endless conveyance belt is stretched around a plurality of rollers. In such a belt conveying device, it is known that the belt conveying speed changes due to variations in the thickness of the conveying belt, which causes color misregistration in images formed on a recording medium.

As a technique to prevent this, Patent Document 1 below describes thickness-rotational speed fluctuation data that corresponds thickness profile data in the circumferential direction of the conveyor belt and encoder detection results due to changes in the thickness of the conveyor belt. , it is stated that the data is stored in non-volatile memory. Further, the CPU determines the position of the conveyor belt corresponding to the driven roller relative to the reference position from the detection result of the magnetic sensor, and based on the position of the driven roller, the CPU determines the position of the driven roller from the thickness-rotational speed fluctuation data in the nonvolatile memory. A drive signal that acquires the fluctuation value of the driven roller rotation speed value of the encoder with respect to the thickness of the conveyor belt at the roller position and outputs it to the driver in order to convey the conveyor belt at a target conveyance speed based on the driven roller rotation speed value of the encoder. It is stated that speed fluctuations due to uneven thickness of the conveyor belt can be prevented by correcting the fluctuation value based on the fluctuation value.

Japanese Patent Application Publication No. 2010-191126

By the way, in the above-mentioned belt conveyance device, the thickness of the conveyor belt decreases over the entire circumference due to wear of the conveyor belt over time. As described above, the thinner conveyor belt changes the belt conveyance speed and becomes more likely to break due to the steering operation during meandering correction, which is a factor that shortens the life of the conveyor belt.

SUMMARY OF THE INVENTION Therefore, it is an object of the present invention to provide a belt conveying device that can prevent breakage of the conveying belt and extend its service life, as well as an image forming apparatus using this belt conveying device, and a method for controlling the belt conveying device. The purpose is to provide

To achieve such an object, the present invention includes an endless conveyor belt, a drive roller disposed on the inner circumference of the conveyor belt to drive the conveyor belt, and a drive roller disposed on the inner circumference of the conveyor belt to drive the conveyor belt. a tension control roller that adjusts the tension of the belt; a drive unit that moves the position of the tension control roller in a direction perpendicular to the axis of the tension control roller; and movement of the tension control roller by the drive unit. a control unit that adjusts the belt tension of the conveyor belt by controlling the belt tension of the conveyor belt, and the control unit adjusts the belt tension of the conveyor belt so that the belt tension reaches a target value set according to the belt thickness of the conveyor belt. This is a belt conveying device that controls a drive unit to move the tension control roller.

According to the present invention, it is possible to provide a belt conveying device that can prevent breakage of the conveying belt and extend its life, and furthermore, to provide an image forming apparatus using this belt conveying device and control of the belt conveying device. method can be provided.

FIG. 1 is a configuration diagram of main parts of an image forming apparatus according to an embodiment. FIG. 2 is a top view of a belt conveying device provided in the image forming apparatus according to the embodiment. FIG. 1 is a main part configuration diagram (part 1) of a belt conveying device provided in an image forming apparatus according to an embodiment. FIG. 2 is a main part configuration diagram (part 2) of a belt conveying device provided in the image forming apparatus according to the embodiment. FIG. 3 is a block diagram of a drive mechanism of the belt conveying device according to the embodiment. It is a figure for explaining setting of belt tension in a belt conveyance device concerning an embodiment. It is a figure for explaining the upper limit of belt tension in a belt conveyance device concerning an embodiment. 3 is a flowchart illustrating a method of controlling the belt conveying device according to the embodiment. 7 is a graph illustrating meandering correction of a belt conveying device provided in an image forming apparatus according to an embodiment.

Embodiments of an image forming apparatus, a belt conveying apparatus provided in the image forming apparatus, and a method of controlling the belt conveying apparatus to which the present invention is applied will be described below in this order. In the following embodiments, an inkjet image forming apparatus is exemplified as an image forming apparatus, but the image forming apparatus of the present invention can be widely applied as long as it has a belt conveying device. Further, the belt conveyance device described in the embodiments is not limited to one provided in an image forming apparatus, and can be widely applied to belt conveyance devices that require high running performance for an endless belt.

≪Image forming device≫
FIG. 1 is a configuration diagram of main parts of an image forming apparatus according to an embodiment, and is a side view of an image forming section in an inkjet image forming apparatus. As shown in this figure, an inkjet type image forming apparatus 1 includes a belt conveying device 1a, an ink supply device 1b, and an operating device 1c.

Among these, the belt conveying device 1a is for conveying the recording medium P in a predetermined direction. As the recording medium P, in addition to ordinary paper materials, cardboard, corrugated paper, and sheet-like materials made of resin materials or cloth materials are widely used.

This belt conveyance device 1a includes a drive roller 10, a driven roller 11, a tension control roller 12, and an endless conveyor belt 13 stretched over these rollers, and rotates the conveyor belt 13 by rotation of the drive roller 10. Thereby, the outer circumferential surface of the conveyor belt 13 is used as a mounting surface 13s for the recording medium P, and the recording medium P held on the mounting surface 13s is conveyed in the circumferential direction of the conveyor belt 13. Such a belt conveying device 1a is equipped with a drive mechanism 20 that is characteristic of this embodiment. The configurations of the belt conveying device 1a and the drive mechanism 20 will be described in detail below.

The ink supply device 1b is for supplying ink to the recording medium P conveyed by the belt conveyance device 1a. The ink supply device 1b has an ink head that supplies ink of each color along the conveyance direction of the recording medium P conveyed by the belt conveyance device 1a. As an example, a configuration is shown in which the yellow ink head 100y, the magenta ink head 100m, the cyan ink head 100c, and the black ink head 100k are arranged in this order along the conveyance direction of the recording medium P, but the arrangement is not limited to this order. do not have.

The operating device 1c is a part for inputting settings for a print job executed using the image forming apparatus 1. Such an operating device 1c includes a display panel and operation buttons, and the operation buttons may be a touch panel provided integrally with the display panel. Note that the operating device 1c that performs such operations may be a personal computer or other external device connected to the image forming apparatus 1. Further, this operating device 1c may be provided as a component of a belt conveying device 1a described below.

The image forming apparatus 1 configured as described above sequentially supplies ink of each color from the ink supply device 1b to the recording medium P being conveyed in a predetermined direction by the belt conveying device 1a. Form an image on P. Next, the configuration of the belt conveying device 1a provided in the image forming apparatus 1 will be explained.

<<Belt conveyance device 1a>>
FIG. 2 is a top view of the belt conveying device 1a provided in the image forming apparatus according to the embodiment. The belt conveying device 1a shown in FIGS. 1 and 2 includes, in addition to the above-described drive roller 10, driven roller 11, tension control roller 12, and conveying belt 13, a support body that supports the conveying belt 13 from the inner peripheral side. 14, a suction fan 15, and a heating device 16. Further, the belt conveying device 1a includes a drive mechanism 20. Below, these configurations will be explained in order.

<Drive roller 10>
Among these, the drive roller 10 is equipped with a drive motor (not shown) and is a roller that freely rotates in a predetermined direction. The drive roller 10 is provided with a rotational speed measurement unit such as a rotary encoder, and the rotational speed is freely controlled by feeding back the rotational speed measured by this measurement unit to the drive motor. The structure is as follows.

<Driven roller 11>
The driven roller 11 is a roller arranged parallel to the drive roller 10 at an interval between which the ink supply device 1b is arranged. The driven roller 11 is rotatable following the rotation of the conveyor belt 13 caused by the rotation of the drive roller 10. The driven roller 11 is provided with a rotary encoder 11a, and the rotational speed measured by the rotary encoder 11a is fed back to the control section of the ink supply device 1b. Thereby, ink of each color is ejected from the ink supply device 1b in synchronization with the conveyance speed of the recording medium P by the belt conveyance device 1a, and a color image is formed on the recording medium P.

<Tension control roller 12>
The tension control roller 12 is a roller disposed between the drive roller 10 and the driven roller 11, approximately parallel to the drive roller 10 and the driven roller 11, and extends from the inner circumference side to the outer circumference side with respect to the conveyor belt 13. Apply pressure to the side. This tension control roller 12 is a driven roller, and here also has a function as a steering roller for controlling the meandering of the conveyor belt 13. Such a tension control roller 12 is equipped with a drive mechanism 20 for controlling the pressure applied to the conveyor belt 13. The configuration of the drive mechanism 20 will be described in detail below.

<Transport belt 13>
The conveyor belt 13 is an endless belt stretched around the drive roller 10 , the driven roller 11 , and the tension control roller 12 . This conveyor belt 13 has a plurality of through holes 13a that allow air to pass between the outer circumferential surface and the inner circumferential surface. These through-holes 13a are provided in the width direction of the conveyor belt 13, corresponding to locations where the recording medium P is placed.

Further, such a conveyor belt 13 is made of steel, for example, but is not limited thereto. This conveyor belt 13 expands and contracts due to temperature changes. Therefore, by being heated by the heating device 16 described below, the length in the circumferential direction is particularly extended.

<Support 14>
The support body 14 is a plate-shaped member that supports the conveyor belt 13 from the inner peripheral side between the drive roller 10 and the driven roller 11. This support body 14 has a plurality of through holes that communicate with through holes 13a provided in the rotating conveyor belt 13 and through which air can pass. Such a support body 14 may be made of a porous material.

Since such a support body 14 supports the conveyor belt 13 while sliding on its support surface, friction is generated between the support body 14 and the conveyor belt 13 . Therefore, the driving of the belt conveying device 1a over time causes the conveying belt 13 to wear out and reduce the belt thickness [t].

<Suction fan 15>
The suction fan 15 is provided between the drive roller 10 and the driven roller 11 on the inner peripheral side of the conveyor belt 13 with the support 14 interposed therebetween. This suction fan 15 sucks air on the mounting surface 13s side of the conveyor belt 13 through the through hole of the support body 14 and the through hole 13a of the conveyor belt 13. By driving the suction fan 15 as described above, the belt conveyance device 1a transfers the recording medium P supplied onto the placement surface 13s of the conveyance belt 13 onto the placement surface 13s between the drive roller 10 and the driven roller 11. The recording medium P in the attracted state is conveyed in the circumferential direction of the conveyor belt 13.

<Heating device 16>
The heating device 16 is for heating the recording medium P on the conveyor belt 13 via the conveyor belt 13, and is constituted by, for example, a heater arranged to sandwich the conveyor belt 13 from both sides. Such a heating device 16 may be configured to heat the recording medium P supplied from the medium supply section to the belt conveying device 1a side. Direct or indirect heating of the conveyor belt 13 by the heating device 16 is a factor in stretching the conveyor belt 13.

<Drive mechanism 20>
3 and 4 are main part configuration diagrams (Part 1) and (Part 2) of the belt conveyance device 1a provided in the image forming apparatus according to the embodiment, and tension control in the belt conveyance device 1a shown in FIG. FIG. 3 is a diagram of the roller 12 viewed from the front side. Further, FIG. 5 is a block diagram of the drive mechanism 20 of the belt conveying device 1a according to the embodiment. Hereinafter, based on these FIGS. 3 to 5, details of the drive mechanism 20 will be explained with reference to FIG. 1, which will be described further.

As shown in these figures, the drive mechanism 20 includes a drive section 21, a pressure detection section 22, a position detection section 23, a belt thickness detection section 24, an edge detection section 25, and a control section 26. Of these, the drive section 21, the pressure detection section 22, and the position detection section 23 are provided at both ends of the tension control roller 12, respectively. As a result, the tension control roller 12 applies pressure to the conveyor belt 13 from the inner circumferential side to the outer circumferential side to control the tension of the conveyor belt 13, and also acts as a steering roller whose positions at both ends can be individually controlled. It is also configured to function. Each member constituting the drive mechanism 20 will be explained below.

[Drive section 21]
The drive unit 21 includes a shaft 21a that rotatably supports both ends of the tension control roller 12, and an actuator 21b that independently moves each shaft 21a in the extending direction. The two shafts 21a are arranged in parallel and extend perpendicularly to the axial direction of the drive roller 10 and the driven roller 11. Thereby, the drive unit 21 simultaneously moves both ends of the tension control roller 12 in a direction perpendicular to the axial directions of the drive roller 10 and the driven roller 11, and controls the tension applied to the conveyor belt 13. For example, when the conveyor belt 13 is stretched by being heated by the heating device 16, the drive unit 21 lowers the two shafts 21a by the same amount to maintain the tension applied to the stretched conveyor belt 13 at a predetermined level. Perform tension correction to maintain the value.

Further, the drive unit 21 moves one end of the tension control roller 12 in a direction perpendicular to the axial directions of the drive roller 10 and the driven roller 11, thereby steering the tension control roller 12. For example, when the conveyor belt 13 is misaligned in the width direction with respect to the reference position and travels in a meandering manner, the drive unit 21 pushes down one of the two shafts 21a. For example, in the example shown in FIG. 4, the shaft 21a on the right side in the drawing is pushed down. As a result, the belt tension on the right side of the conveyor belt 13 is increased, and the conveyor belt 13 is moved to the left and returned to the reference position. Note that the procedure of the operation of the tension control roller 12 by the drive unit 21 as described above will be explained in detail in the subsequent control method of the belt conveying device 1a.

[Pressure detection unit 22]
The pressure detection unit 22 is a load cell for detecting the pressure applied to the tension control roller 12 by the conveyor belt 13 stretched around the tension control roller 12 . The pressure detected by the pressure detection unit 22 is the pressure directed toward the inner peripheral side of the conveyor belt 13 in the extending direction of the shaft 21a of the drive unit 21, and depends on the tension applied to the conveyor belt 13. Such a pressure detection section 22 continuously detects the pressure applied to the tension control roller 12.

[Position detection unit 23]
The position detection unit 23 is for detecting the position of the end of the tension control roller 12 that is moved by the drive unit 21, and the position in the extending direction of the shaft 21a. This position detection section 23 may be provided, for example, in an actuator control section included in each of the actuators 21b of the two drive sections 21. The position detection unit 23 detects the position of the end of the tension control roller 12 based on the drive position of the actuator 21b. Such a position detection unit 23 continuously detects the position of the end of the tension control roller 12.

[Belt thickness detection section 24]
The belt thickness detection section 24 is for detecting the thickness of the conveyor belt 13. The belt thickness detection unit 24 is, for example, a distance measuring sensor disposed facing the conveyor belt 13 at a position where the conveyor belt 13 is sandwiched between the driven roller 11 and, for example, a reflective optical sensor. It may be.

[Edge detection unit 25]
The edge detection unit 25 measures the position of one of the edges on both sides of the conveyor belt 13 as the amount of deviation from the reference position. Such an edge detection section 25 continuously detects the position of the edge of the conveyor belt 13.

[Control unit 26]
The control section 26 is connected to the two drive sections 21 , the pressure detection section 22 , the position detection section 23 , the belt thickness detection section 24 , and the edge detection section 25 . Such a control section 26 controls the operation of the tension control roller 12 by the two drive sections 21 based on the values detected by the pressure detection section 22, the position detection section 23, the belt thickness detection section 24, and the edge detection section 25. Control. The control unit 26 controls the operation of the tension control roller 12 so that the conveyor belt 13 rotates with good running performance without slipping or meandering. Such a control section 26 includes an input/output control section 26a, a storage section 26b, and a set value extraction section 26c. These details will be explained below.

-Input/output control section 26a-
The input/output control section 26a includes the drive section 21 (more specifically, the actuator 21b of the drive section 21), the pressure detection section 22, the position detection section 23, the belt thickness detection section 24, the edge detection section 25, and the storage section described above. 26b and the setting value extraction section 26c. Further, the input/output control section 26a is connected to the drive roller 10, the suction fan 15, the heating device 16, and further to the operating device 1c.

The input/output control section 26a operates based on the values detected by the pressure detection section 22, the position detection section 23, the belt thickness detection section 24, and the edge detection section 25, and the data stored in the storage section 26b. The drive of the section 21 is controlled. Further, the input/output control section 26a controls the driving of the drive roller 10, the suction fan 15, and the heating device 16. Details of such control by the input/output control section 26a will be explained in the following description of the belt conveying device control method.

Such an input/output control unit 26a is hardware used as a computer, and is configured by a computer. The computer includes a CPU (Central Processing Unit), a RAM (Random Access Memory), and non-volatile storage units such as a ROM (Read Only Memory) and an HDD (hard disk drive), all of which are not shown here. However, by executing a program recorded in the ROM or RAM, the control method for the belt conveying device 1a described below is implemented.

-Storage section 26b-
The storage unit 26b is a ROM or RAM that stores each set value regarding the belt tension associated with the belt thickness [t] of the conveyor belt 13. FIG. 6 is a diagram for explaining various settings related to belt tension in the belt conveying device according to the embodiment. As shown in FIG. 6, each set value regarding belt tension associated with belt thickness [t] of the conveyor belt 13 is upper limit value [Tmax], corrected allowable tension [Tc]/corrected movement amount [dc], corrected They are the previous upper limit value [T1] and the target value [Td]. Note that this belt thickness [t] is a value detected by the belt thickness detection unit 24 when a constant belt tension is applied to the conveyor belt 13. At this time, the constant belt tension applied to the conveyor belt 13 is a value that allows the conveyor belt 13 of each belt thickness [t] to run without slipping, and is 400 (N) as an example.

First, the upper limit value [Tmax] is the maximum value of the tension that can be applied to the conveyor belt of each belt thickness [t]. Such upper limit value [Tmax] is a value experimentally determined for each conveyor belt having a different configuration such as length, width, material, and arrangement of through holes, and for each belt conveyor 1a. , is the maximum value at which the conveyor belt remains elastically deformable. FIG. 7 is a diagram for explaining the upper limit value [Tmax] of belt tension in the belt conveyance device according to the embodiment, and shows the belt tension applied to the conveyance belt and the belt tension applied to the conveyance belt at each belt thickness [t]. It is a graph showing the relationship with the stretching ratio.

As shown in the graph of FIG. 7, the conveyor belt having each belt thickness [t] is stretched as the applied belt tension [T] increases, and the first stretching rate [A] (1. 25%), elasticity is lost and the material becomes plastically deformable. Further, the conveyor belt having each belt thickness [t] breaks when it reaches the second stretching ratio [B] (1.3% in the illustrated example).

Therefore, for each belt thickness [t] of the conveyor belt, the maximum value of the belt tension at which the conveyor belt is kept in the elastic deformation region, that is, the value corresponding to the above-mentioned first stretching ratio [A], is determined as the upper limit value of the belt tension [ Tmax]. FIG. 6 shows the upper limit value [Tmax] for each belt thickness [t] set in this way.

Further, the correction allowable tension [Tc] is the upper limit value of the belt tension required to effectively correct the meandering of the conveyor belt 13 by the steering operation of the tension control roller 12 explained using FIG. , is the upper limit value of the belt tension that can be added to the conveyor belt 13. Such a corrected allowable tension [Tc] is set as a constant value regardless of the belt thickness [t] of the conveyor belt 13, and here, as an example, 50 (N) is set as the corrected allowable tension [Tc]. There is.

Further, the correction movement amount [dc] is the amount by which the shaft 21a is pushed down when the correction allowable tension [Tc] is additionally applied to the conveyor belt 13 with a predetermined belt tension, that is, the movement amount of the end of the tension control roller 12. It is. This corrected movement amount [dc] depends on the belt thickness [t] of the conveyor belt 13, and becomes a larger value as the belt thickness [t] of the conveyor belt 13 increases.

Further, the pre-correction upper limit value [T1] is the maximum value of the tension that can be applied to the conveyor belt of each belt thickness [t] in a state where the above-described meandering correction of the conveyor belt 13 is not performed. Such a pre-correction upper limit value [T1] is a value obtained by subtracting the corrected allowable tension [Tc] from the upper limit value [Tmax] for each belt thickness [t], as shown in equation (1) below.
[T1] = [Tmax] - [Tc]...(1)

Further, the target value [Td] is a set value of the belt tension to be applied to the conveyor belt 13 of each belt thickness [t]. This target value [Td] is a tension that allows the conveyor belt 13 to run without slipping within a range below the pre-correction upper limit value [T1]. Such a target value [Td] is set to a value such that the sum of the target value [Td] and the corrected allowable tension [Tc] does not exceed the upper limit value [Tmax] of belt tension, as shown in equation (2) below. Set. Here, as an example, a value obtained by subtracting a margin of 50 (N) from the pre-correction upper limit value [T1] is set as the target value [Td].
[Td]+[Tc]≦[Tmax]…(2)

-Setting value extraction section 26c-
Returning to FIG. 5, the setting value extraction unit 26c extracts a target setting value from among the belt tension setting values stored in the storage unit 26b according to instructions from the input/output control unit 26a.

≪Control method of belt conveying device≫
FIG. 8 is a flowchart showing a method of controlling the belt conveying device according to the embodiment. The method of controlling the belt conveying device shown in this flowchart is a method of controlling the belt conveying device 1a that is implemented in the control section 26 of the drive mechanism 20 described above. Hereinafter, the procedure of the control method for the belt conveying device 1a will be explained along the flowchart of FIG. 8 and with reference to FIGS. 1 to 7. The process shown in the flowchart of FIG. 8 is started, for example, when the power of the belt conveying device 1a or the image forming apparatus including the belt conveying device 1a is turned on.

[Step S101]
In step S101, the input/output control unit 26a performs belt tension equalization processing on the conveyor belt 13. At this time, the input/output control section 26a drives the drive section 21 based on the pressure detected by the pressure detection section 22, and applies a predetermined belt tension to the conveyor belt 13. The belt tension applied here is a constant belt tension when each belt thickness [t] shown in FIG. 6 is measured, and is 400 (N) as an example.

Next, the input/output control unit 26a drives the drive roller 10 to rotate the conveyor belt 13 at least once while applying a constant belt tension to the conveyor belt 13. This makes the tension applied to the conveyor belt 13 uniform in the circumferential direction.

[Step S102]
In step S102, the input/output control section 26a causes the belt thickness detection section 24 to measure the belt thickness [t] of the conveyor belt 13. At this time, the input/output control unit 26a heats the conveyor belt 13 to a predetermined temperature using the heating device 16. Next, the drive roller 10 is driven to rotate the conveyor belt 13, the belt thickness detection unit 24 measures the belt thickness [t] for one revolution of the conveyor belt 13, and the lowest value of the measured values is determined as the belt thickness. Let it be [t].

[Step S103]
In step S103, the input/output control unit 26a determines whether the belt thickness [t] obtained in step S102 is equal to or greater than a preset lower limit value. Here, it is assumed that the preset lower limit value is a magnitude at which it is determined that the conveyor belt 13 needs to be replaced. Here, as an example, if it is determined that replacement is necessary when the belt thickness [t] of the conveyor belt 13 becomes less than 50 μm, 50 μm is preset as the lower limit, and the belt thickness [t] obtained in step S102 is determined to be necessary. is equal to or greater than the lower limit of 50 μm.

If it is determined that it is equal to or higher than the lower limit (YES), the process advances to the next step S104. On the other hand, if it is determined that it is not equal to or greater than the lower limit (NO), the process advances to the next step S103a.

[Step S103a]
In step S103a, the input/output control unit 26a sends a notification to the operating device 1c to prompt replacement of the conveyor belt 13, and ends the process. Upon receiving this notification, the operating device 1c displays a notification to replace the conveyor belt 13.

[Step S104]
In step S104, the input/output control unit 26a asks the setting value extraction unit 26c to select a belt tension target corresponding to the belt thickness [t] obtained in step S102 from among the setting values stored in the storage unit 26b. The value [Td] and the corrected movement value [dc] are extracted. Here, for example, if the belt thickness [t] obtained in step S102 is 85 (μm), the target value [Td] = 350 (N) and the corrected movement value [dc] = 0.90 (mm). Extracted.

[Step S105]
In step S105, the input/output control unit 26a drives the drive unit 21 based on the pressure detected by the pressure detection unit 22, and adjusts the belt tension of the conveyor belt 13 to the target value [Td] = 350 ( N). In this state, the conveyor belt 13 is rotated at least once. Thereby, the tension applied to the conveyor belt 13 is made uniform.

[Step S106]
In step S106, the input/output control unit 26a performs meandering correction of the conveyor belt 13. At this time, the input/output control section 26a feeds back the amount of deviation of the edge position of the conveyor belt 13 from the reference position detected by the edge detection section 25, and drives the drive section 21 so that this amount of deviation becomes zero. control. At this time, the input/output control unit 26a controls the actuator so that the upper limit of the amount of movement of one end of the tension control roller 12 is the corrected movement value [dc] = 0.90 (mm) extracted in step S104. 21b. It is preferable to apply PID (Proportinal Integral Derivative) control to this control, thereby implementing smooth meandering control.

FIG. 9 is a graph illustrating meandering correction of the belt conveying device 1a provided in the image forming apparatus according to the embodiment. As shown in this figure, the input/output control unit 26a operates the actuator 21b to push down one of the edges of the tension control roller 12 based on the amount of deviation of the conveyor belt 13 detected by the edge detection unit 25. drive. At this time, the maximum value of the movement amount of the end portion of the tension control roller 12 is set to the corrected movement value [dc]. In such a drive, when the difference between the edge position of the conveyor belt 13 and the reference position becomes small and the edge position passes the reference position, the edge of the tension control roller 12 that has been pushed down is pulled back.

The input/output control unit 26a repeats such driving of the actuator 21b while feeding back the amount of deviation of the edge position of the conveyor belt 13 detected by the edge detection unit 25. Thereby, the deviation amount of the edge position is converged to zero and the meandering correction is performed. In addition, one of the edges of the tension control roller 12 moved by the drive of the actuator 21b is also converged to the original position, thereby increasing the belt tension of the conveyor belt 13 to the target value [Td] = 350 (N). return.

In this state, the conveyor belt 13 is rotated at least once. Thereby, the tension applied to the conveyor belt 13 is made uniform.

[Step S107]
In step S107, the input/output control unit 26a notifies the operating device 1c of permission to start printing the job. Upon receiving this notification, the operating device 1c causes the belt conveying device 1a and the ink supply device 1b to perform a job printing operation.

[Step S108]
In step S108, the input/output control unit 26a determines whether or not to perform correction. This determination is performed regarding belt tension correction and meandering correction. The determination as to whether or not to perform these corrections is made based on whether a preset correction timing has been reached or based on the values fed back from the pressure detection section 22 and the edge detection section 25. judged by or both. If it is determined that the correction is to be performed (YES), the process advances to the next step S109. If it is determined that the correction is not to be performed (NO), the process proceeds to step S110.

[Step S109]
In step S109, the input/output control unit 26a performs the same procedure as described in step S105 if the belt tension is to be corrected. On the other hand, in the case of meandering correction, a procedure similar to that described in step S106 is performed.

[Step S110]
In step S110, the input/output control unit 26a determines whether an input to turn off the power has been made. If it is determined that the power is off (YES), the process advances to step S111, and if it is determined that the power is not off (NO), the process returns to step S108.

[Step S111]
In step S111, the input/output control unit 26a drives the drive unit 21 to set the belt tension applied to the conveyance belt 13 to a preset standby belt tension and terminate the process. Here, it is assumed that the belt tension during standby is set to a value that suppresses the load on the conveyor belt 13 as small as possible.

<Effects of embodiment>
According to the image forming apparatus 1, the belt conveyance apparatus 1a, and the control method of the belt conveyance apparatus of the embodiments described above, the target value [Tc] and the upper limit value of the belt tension corresponding to the belt thickness [t] of the conveyance belt 13 are obtained. [Tmax] is set, and based on this set value, steering operation for belt tension adjustment and meandering correction is performed. Therefore, unreasonable belt tension is not applied to the conveyor belt 13, and breakage of the conveyor belt 13 is prevented, making it possible to extend the life of the conveyor belt 13.

1 Image forming device 1a Belt conveyance device 1b Ink supply device 1c Operating device 10 Drive roller 11 Followed roller 11a Rotary encoder 12 Tension control roller 13 Conveyance belt 14 Support body 16 Heating device 20 Drive mechanism 21 Drive section 21a Shaft 21b Actuator 22 Pressure detection Section 23 Position detection section 24 Belt thickness detection section 25 Edge detection section 26 Control section 26a Input/output control section 26b Storage section 26c Set value extraction section [dc]...Correction movement amount [t]...Belt thickness [Td]...Target value [ Tmax]...Upper limit

Claims (16)

An endless conveyor belt,
a drive roller disposed on the inner periphery of the conveyor belt and driving the conveyor belt;
a tension control roller arranged on the inner periphery of the conveyor belt and adjusting the tension of the conveyor belt;
a drive unit for moving the position of the tension control roller in a direction perpendicular to the axis of the tension control roller;
a control unit that adjusts belt tension of the conveyor belt by controlling movement of the tension control roller by the drive unit,
The drive unit has a configuration that independently moves both ends of the tension control roller,
The control unit includes:
controlling the drive unit to move the tension control roller so that the belt tension reaches a target value set according to the belt thickness of the conveyor belt;
Controlling the drive unit to move the position of one end of the tension control roller up to a correction movement amount set according to the belt thickness of the conveyor belt, and correcting the meandering of the conveyor belt. do
Belt conveyor device. The belt conveying device according to claim 1, wherein the control section includes a storage section that stores data associating the belt thickness with the target value of the belt tension. comprising a belt thickness detection unit that measures the belt thickness of the conveyor belt,
The belt conveyance device according to claim 2, wherein the control section extracts the target value from the storage section based on the belt thickness obtained by the belt thickness detection section. comprising a pressure detection unit for detecting the pressure applied to the tension control roller by the conveyor belt,
The control unit controls the drive unit to move the tension control roller so that the belt tension of the conveyor belt reaches the target value based on the pressure detected by the pressure detection unit. 3. The belt conveying device according to any one of items 3 to 3. The belt conveying device according to any one of claims 1 to 4, wherein the control unit includes a storage unit that stores data associating the belt thickness with the corrected movement amount. The target value and the belt tension are set such that the sum of the target value and the belt tension applied to the conveyor belt corresponding to the corrected movement amount is equal to or less than the upper limit value of the belt tension set according to the belt thickness. The belt conveying device according to any one of claims 1 to 5, wherein a correction movement amount is set. The belt conveyance device according to claim 6 , wherein the upper limit of the belt tension is the upper limit of a range in which the conveyor belt can be elastically deformed. comprising an edge position detection unit that measures the amount of deviation of the edge position of the conveyor belt,
The control unit controls the drive unit based on the amount of deviation obtained by the edge position detection unit, and performs meandering correction of the conveyor belt. Belt conveyor device. The belt conveyance device according to any one of claims 1 to 8, wherein the belt thickness of the conveyance belt is a value measured with a predetermined belt tension applied to the conveyance belt. The belt thickness of the conveyor belt is the smallest value among the values measured for the conveyor belt stretched between the drive roller and the tension control roller. Belt conveyance device described in. Any one of claims 1 to 10 , wherein the belt thickness of the conveyor belt is the smallest value among the values measured for the entire circumference of the conveyor belt stretched between the drive roller and the tension control roller. 2. The belt conveying device according to item 1. The belt conveyance device according to any one of claims 1 to 11 , further comprising a heating device that heats the conveyance belt. The belt conveyance device according to any one of claims 1 to 12 , further comprising a notification section for notifying when the belt thickness of the conveyance belt is smaller than a preset lower limit value. An image forming apparatus comprising the belt conveying device according to any one of claims 1 to 13 . an endless conveyor belt, a drive roller disposed on the inner circumference of the conveyor belt to drive the conveyor belt, a tension control roller disposed on the inner circumference of the conveyor belt to adjust the tension of the conveyor belt, and the tension control roller a drive section for independently moving both ends of a control roller in a direction perpendicular to the axis of the tension control roller; and a belt of the conveyor belt by controlling movement of the tension control roller by the drive section. A control method for a belt conveying device comprising a control unit for adjusting tension, the method comprising:
The control unit controls the driving unit to move the tension control roller so that the belt tension reaches a target value set according to the belt thickness of the conveyor belt, and the belt tension of the conveyor belt is controlled by the control unit to move the tension control roller. Controlling the drive unit to move the position of one end of the tension control roller with a correction movement amount set according to the thickness as an upper limit, and correcting the meandering of the conveyor belt.
A method of controlling a belt conveying device. After the rotation of the conveyor belt by the drive roller is completed,
The method for controlling a belt conveying device according to claim 15 , wherein the control section loosens the belt tension applied to the conveyance belt by controlling movement of the tension control roller by the drive section.

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